How it works
An attacker who already controls a friend's account messages you, sounding just like them. They ask for a small favour: vote for them in a competition, or confirm a code that was sent to you by mistake.
That code is actually the verification or password-reset code for your own account. The moment you forward it, the attacker resets your login, locks you out and starts the same routine on everyone in your contacts.
Why it works and who is targeted
The request comes from a real friend's account, so it feels completely safe - you are not talking to a stranger but to someone you trust. The favour sounds tiny and harmless, which lowers any suspicion.
Anyone with an online account is a potential target, but people who are quick to help friends, and those less familiar with how login codes work, are most at risk. The scam scales by turning each new victim into a launchpad for the next.
Red flags in detail
Any request to share a verification code, one-time password or reset code is the brightest red flag - those codes are only ever for you, never for anyone else. Be alert when a contact suddenly needs help getting back into an account, or asks you to vote via a strange link.
Messages that create urgency, ask for money, or sound slightly off in tone or wording suggest the account is compromised. A request that arrives only by chat, with the friend unable to take a call, is especially suspicious.
What to do and how to stay safe
Never share a login or verification code with anyone, no matter who appears to be asking. If a friend's message seems off, verify through another channel - call them or message a different way before doing anything.
Protect your own accounts with strong, unique passwords and turn on two-factor authentication, ideally with an app rather than text messages. If you receive a code you did not request, treat it as an attempt against you and ignore it.